A kind of thermo-sensitive core/shell nanoparticles (Mn-Zn ferrite/poly(N,N'-isopropylacrylamide-co-N-hydroxymethylacrylamide)) has been designed in this work. By using the surface initiated method, a thermoresponsive co-polymer composed of N,N'-isopropylacrylamide (NIPAAm) and N-hydroxymethylacrylamide (HMAAm) was grafted from ferrite core. The nanoparticles obtained were characterized by FT-IR, XRD, TGA, HRTEM and DLS. The HRTEM observation showed a clear contrast between an ordered crystalline core and a light amorphous polymeric coating. DLS results confirmed the temperature sensitivity of the nanoparticles. In vitro hyperthermia showed well-controlled self-heating properties, indicating that the nanoparticles could potentially be used as an anticancer drug carrier in the biomedical field.